| Parameter |
Value |
| Designation |
28P/Neujmin 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-03-12T01:00:53.363520Z |
| Orbit solution date (soln_date, UTC) |
2026-06-05T08:28:30Z |
| Obs used |
1228 |
| NEO |
- |
| M1 |
13.200 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-09-01.0000000 |
| e |
0.77345394 |
| q (au) |
1.577999 |
| a (au) |
6.965466 |
| i (deg) |
14.311489 |
| Ω (om, deg) |
346.346287 |
| ω (w, deg) |
347.442917 |
| M (ma, deg) |
330.081078 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.735 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.735 |
| n |
2.000 |
| gf |
0.891 |
| gb |
-0.727 |
| k |
0.939 |
| δ90 |
1.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
09:08:01.69 |
+23:34:07.3 |
HIP 44941 |
17.08 |
| 2026-06-01 12:00 |
09:08:08.06 |
+23:33:17.9 |
HIP 44941 |
15.48 |
| 2026-06-02 00:00 |
09:08:14.51 |
+23:32:28.4 |
HIP 44941 |
13.88 |
| 2026-06-02 12:00 |
09:08:21.03 |
+23:31:38.7 |
HIP 44941 |
12.29 |
| 2026-06-03 00:00 |
09:08:27.61 |
+23:30:48.7 |
HIP 44941 |
10.72 |
| 2026-06-03 12:00 |
09:08:34.27 |
+23:29:58.6 |
HIP 44941 |
9.19 |
| 2026-06-04 00:00 |
09:08:41.00 |
+23:29:08.2 |
HIP 44941 |
7.73 |
| 2026-06-04 12:00 |
09:08:47.80 |
+23:28:17.7 |
HIP 44941 |
6.40 |
| 2026-06-05 00:00 |
09:08:54.67 |
+23:27:26.9 |
HIP 44941 |
5.33 |
| 2026-06-05 12:00 |
09:09:01.60 |
+23:26:36.0 |
HIP 44941 |
4.71 |
| 2026-06-06 00:00 |
09:09:08.60 |
+23:25:44.8 |
HIP 44941 |
4.74 |
| 2026-06-06 12:00 |
09:09:15.67 |
+23:24:53.5 |
HIP 44941 |
5.41 |
| 2026-06-07 00:00 |
09:09:22.81 |
+23:24:01.9 |
HIP 44941 |
6.56 |
| 2026-06-07 12:00 |
09:09:30.02 |
+23:23:10.2 |
HIP 44941 |
7.98 |
| 2026-06-08 00:00 |
09:09:37.29 |
+23:22:18.3 |
HIP 44941 |
9.57 |
| 2026-06-08 12:00 |
09:09:44.62 |
+23:21:26.2 |
HIP 44941 |
11.26 |
| 2026-06-09 00:00 |
09:09:52.02 |
+23:20:33.9 |
HIP 44941 |
13.02 |
| 2026-06-09 12:00 |
09:09:59.49 |
+23:19:41.4 |
HIP 44941 |
14.83 |
| 2026-06-10 00:00 |
09:10:07.02 |
+23:18:48.7 |
HIP 44941 |
16.67 |
| 2026-06-10 12:00 |
09:10:14.61 |
+23:17:55.9 |
HIP 44941 |
18.55 |
| 2026-06-11 00:00 |
09:10:22.27 |
+23:17:02.9 |
HIP 44941 |
20.46 |
| 2026-06-11 12:00 |
09:10:29.99 |
+23:16:09.7 |
HIP 44941 |
22.39 |
| 2026-06-12 00:00 |
09:10:37.77 |
+23:15:16.3 |
HIP 44941 |
24.34 |
| 2026-06-12 12:00 |
09:10:45.61 |
+23:14:22.8 |
HIP 44941 |
26.31 |
| 2026-06-13 00:00 |
09:10:53.51 |
+23:13:29.1 |
HIP 44941 |
28.30 |
| 2026-06-13 12:00 |
09:11:01.48 |
+23:12:35.2 |
HIP 44941 |
30.31 |
| 2026-06-14 00:00 |
09:11:09.51 |
+23:11:41.1 |
HIP 44941 |
32.33 |
| 2026-06-14 12:00 |
09:11:17.59 |
+23:10:46.9 |
HIP 44941 |
34.37 |
| 2026-06-15 00:00 |
09:11:25.73 |
+23:09:52.6 |
HIP 45004 |
35.52 |
| 2026-06-15 12:00 |
09:11:33.94 |
+23:08:58.0 |
HIP 45004 |
35.91 |
| 2026-06-16 00:00 |
09:11:42.20 |
+23:08:03.4 |
HIP 45004 |
36.42 |
| 2026-06-16 12:00 |
09:11:50.52 |
+23:07:08.5 |
HIP 45004 |
37.05 |
| 2026-06-17 00:00 |
09:11:58.89 |
+23:06:13.5 |
HIP 45004 |
37.80 |
| 2026-06-17 12:00 |
09:12:07.32 |
+23:05:18.4 |
HIP 45004 |
38.66 |
| 2026-06-18 00:00 |
09:12:15.81 |
+23:04:23.1 |
HIP 45004 |
39.62 |
| 2026-06-18 12:00 |
09:12:24.35 |
+23:03:27.7 |
HIP 45379 |
39.98 |
| 2026-06-19 00:00 |
09:12:32.95 |
+23:02:32.1 |
HIP 45379 |
37.81 |
| 2026-06-19 12:00 |
09:12:41.60 |
+23:01:36.4 |
HIP 45379 |
35.63 |
| 2026-06-20 00:00 |
09:12:50.30 |
+23:00:40.6 |
HIP 45379 |
33.44 |
| 2026-06-20 12:00 |
09:12:59.06 |
+22:59:44.6 |
HIP 45379 |
31.24 |
| 2026-06-21 00:00 |
09:13:07.87 |
+22:58:48.5 |
HIP 45379 |
29.03 |
| 2026-06-21 12:00 |
09:13:16.73 |
+22:57:52.3 |
HIP 45379 |
26.82 |
| 2026-06-22 00:00 |
09:13:25.64 |
+22:56:55.9 |
HIP 45379 |
24.60 |